For nearly four months, the spread of bird flu in the nation’s dairy cattle has stoked fears that, if left unchecked, the virus could eventually unleash a pandemic. The recent cluster of human cases connected to poultry farms in Colorado only underscores that the threat remains real. Genetic sequencing of the virus collected from the sickened poultry workers closely resembles what’s circulating in dairy herds, suggesting that cattle somehow introduced the virus into the poultry flock.
At one massive poultry facility, workers culled the birds under particularly dangerous circumstances. As health officials describe it, they struggled to properly wear protective equipment over their mouth, nose and eyes as they handled thousands of sick birds in a sweltering barn, with industrial fans blowing feathers and other potentially virus-laden material into the air. Given these conditions, it’s far from surprising that people would catch the virus themselves, says Jennifer Nuzzo , an epidemiologist at Brown University.
“It’s gambling with people’s lives,” she says. “There’s no other way to describe it.” State and federal health officials are still investigating the scope of the outbreak, although so far all of those who’ve tested positive have only had mild, flu-like symptoms.
Nuzzo says the spillover at the poultry farms drives home the risks of having a viral reservoir in dairy herds that offers many opportunities for the virus to jump between species and potentia.